It harkens back to a day when "the only good injun is a dead one" and post 9/11 when "All Muslims are terrorists" and the current belief that "illegal immigrants are all criminals", when illegal entry is a civil offense, NOT a criminal one.

Americans, like so many other countries and cultures, believe that any group who has some amongst them those who've committed atrocities or crimes means that ALL OF THEM are the same who embrace the evil committed.